var a = [null].join();
var b = [,].join();
var c = [, 1, , 3].join();
var d = [foo].join();
var e = [foo, null, undefined, bar].join("-");
var f = [foo, bar].join("");
var g = [null, "foo", null, bar + "baz"].join("");
var h = [null, "foo", null, bar + "baz"].join("-");
var i = ["foo" + bar, null, baz + "moo"].join("");
var j = [foo + "bar", baz].join("");
var k = [foo, "bar" + baz].join("");
var l = [foo, bar + "baz"].join("");
